1. Field of the Invention
This invention relates generally to semiconductor manufacturing, and more particularly, to a method and apparatus for providing predicted end of line (EOL) data.
2. Description of the Related Art
The technology explosion in the manufacturing industry has resulted in many new and innovative manufacturing processes. Today's manufacturing processes, particularly semiconductor manufacturing processes, call for a large number of important steps. These process steps are usually vital, and therefore, require a number of inputs that are generally fine-tuned to maintain proper manufacturing control.
The manufacture of semiconductor devices requires a number of discrete process steps to create a packaged semiconductor device from raw semiconductor material. The various processes, from the initial growth of the semiconductor material, the slicing of the semiconductor crystal into individual wafers, the fabrication stages (etching, doping, ion implanting, or the like), to the packaging and final testing of the completed device, are so different from one another and specialized that the processes may be performed in different manufacturing locations that contain different control schemes.
Generally, a set of processing steps is performed across a group of semiconductor wafers, sometimes referred to as a lot. For example, a process layer that may be composed of a variety of different materials may be formed across a semiconductor wafer. Thereafter, a patterned layer of photoresist may be formed across the process layer using known photolithography techniques. Typically, an etch process is then performed across the process layer using a patterned layer of photoresist as a mask. This etching process results in the formation of various features or objects in the process layer. Such features may be used as, for example, a gate electrode structure for transistors. Many times, trench isolation structures are also formed across the substrate of the semiconductor wafer to isolate electrical areas across a semiconductor wafer. One example of an isolation structure that can be used is a shallow trench isolation (STI) structure.
The manufacturing tools within a semiconductor manufacturing facility typically communicate with a manufacturing framework or a network of processing modules. Each manufacturing tool is generally connected to an equipment interface. The equipment interface is connected to a machine interface to which a manufacturing network is connected, thereby facilitating communications between the manufacturing tool and the manufacturing framework. The machine interface can generally be part of an advanced process control (APC) system. The APC system initiates a control script, which can be a software program that automatically retrieves the data needed to execute a manufacturing process.
FIG. 1 illustrates a typical semiconductor wafer 105. The semiconductor wafer 105 typically includes a plurality of individual semiconductor die 103 arranged in a grid 150. Using known photolithography processes and equipment, a patterned layer of photoresist may be formed across one or more process layers that are to be patterned. As part of the photolithography process, an exposure process is typically performed by a stepper on single or multiple die 103 locations at a time, depending on the specific photomask employed. The patterned photoresist layer can be used as a mask during etching processes, wet or dry, performed on the underlying layer or layers of material, e.g., a layer of polysilicon, metal or insulating material, to transfer the desired pattern to the underlying layer. The patterned layer of photoresist is comprised of a plurality of features, e.g., line-type features or opening-type features that are to be replicated in an underlying process layer.
Turning now to FIG. 2, a flowchart depiction of an illustrative prior art process flow is provided. A manufacturing system may determine a type of product that is to be manufactured (block 210). This leads to a step of determining process control parameters for processing a batch of semiconductor wafers 105. A predetermined plan for processing wafers to achieve a certain type of result may be determined (block 220). Based upon this processing plan, the manufacturing system directs various factory components to perform a series of processes upon a batch of semiconductor wafers 105 (block 230). A number of control parameters for controlling the processing of wafers 105 are predetermined. These parameters are then used to control various aspects of processing operations, including scheduling, routing, controlling tool operations, etc.
After processing the semiconductor wafer 105, the manufacturing system may acquire data relating to post-process results (block 240). The data relating to post-process results may include yield data, certain performance parameters relating to the completed product, (e.g., access speed, processing speeds, and the like), etc. Based upon this post-process data, process operations performed on subsequent wafers may be adjusted (block 240). Post-process results may provide insight to various adjustments that can be made to improve process operations, such that improved post-process results relating to subsequently processed wafers may be realized.
However, there are problems associated with the state-of-the-art methodology. For example, a significant amount of time may elapse from the start of process operations to the time period when post-process results are acquired. Often, several weeks may elapse before post-process results are available. In the meantime, several process steps may be performed without the benefit of post-process analysis. Thus, any improvements to process operations that may have been made based upon the knowledge derived from analyzing post-process results, may not be realized.
Various components of a manufacturing system, such as a scheduling controller, routing controller, process controller, etc. may benefit from post-process results. However, state-of-the-art process operations generally involve significant lapse of time before corrective data derived from post-process results is available. This may cause errors relating to post process results; errors that otherwise may have been reduced.
The present invention is directed to overcoming, or at least reducing, the effects of one or more of the problems set forth above.